1. Field of the Invention
The present invention is in the technical field of optical communication.
2. Description of Related Art
Prior art optical transmission systems comprising a primary optical node and at least one secondary optical node require complex and costly components not only at the primary optical node but also at the secondary optical nodes in order to ensure a precise setting of especially upstream transmission wavelengths and downstream receive filter equipment.
Accordingly, it is an object of the present invention to provide an improved primary optical node, particularly an optical line terminal, OLT, for an optical communications system, which enables an efficient wavelength tuning with a plurality of secondary optical nodes, e.g. ONUs, without requiring complex hardware such as wavelength lockers and the like at the ONUs.